diff -up thunderbird-45.4.0/mozilla/configure.in.pgo thunderbird-45.4.0/mozilla/configure.in --- thunderbird-45.4.0/mozilla/configure.in.pgo 2016-10-01 22:57:35.758907539 +0200 +++ thunderbird-45.4.0/mozilla/configure.in 2016-10-01 23:39:20.858686486 +0200 @@ -2114,7 +2114,7 @@ ia64*-hpux*) # while; Intel recommends against using it. MOZ_OPTIMIZE_FLAGS="-O2" elif test "$GNU_CC" -o "$GNU_CXX"; then - MOZ_PGO_OPTIMIZE_FLAGS="-O3" + MOZ_PGO_OPTIMIZE_FLAGS="-O2" MOZ_OPTIMIZE_FLAGS="" if test -z "$CLANG_CC"; then MOZ_OPTIMIZE_FLAGS="-freorder-blocks $MOZ_OPTIMIZE_FLAGS" diff -up thunderbird-45.4.0/mozilla/js/src/configure.in.pgo thunderbird-45.4.0/mozilla/js/src/configure.in --- thunderbird-45.4.0/mozilla/js/src/configure.in.pgo 2016-10-01 22:57:35.758907539 +0200 +++ thunderbird-45.4.0/mozilla/js/src/configure.in 2016-10-01 23:44:08.571989111 +0200 @@ -1650,7 +1650,7 @@ ia64*-hpux*) # while; Intel recommends against using it. MOZ_OPTIMIZE_FLAGS="-O2" elif test "$GNU_CC" -o "$GNU_CXX"; then - MOZ_PGO_OPTIMIZE_FLAGS="-O3" + MOZ_PGO_OPTIMIZE_FLAGS="-O2" MOZ_OPTIMIZE_FLAGS="-O2" if test -z "$CLANG_CC"; then MOZ_OPTIMIZE_FLAGS="-freorder-blocks $MOZ_OPTIMIZE_FLAGS"